'use strict'
const path = require('path')
const defaultSettings = require('./src/settings.js')
const CompressionPlugin = require('compression-webpack-plugin')
const productionGzipExtensions = ['js', 'css']

function resolve(dir) {
  return path.join(__dirname, dir)
}

const name = defaultSettings.title || 'vue Element Admin' // page title

module.exports = {
  publicPath: './',
  outputDir: 'dist',
  assetsDir: '',
  // lintOnSave: process.env.NODE_ENV === 'development',
  lintOnSave: false,
  productionSourceMap: false,
  devServer: {
    // port: port,
    open: true,
    overlay: {
      warnings: false,
      errors: true
    },
  },
  configureWebpack: {
    externals: {
      'vue': 'Vue',
      'element-ui': 'ELEMENT',
      'echarts': 'echarts',
      'vue-router': 'VueRouter',
      'vuex': 'Vuex',
      'axios': 'axios',
      'jszip': 'JSZip',
      'xlsx': 'XLSX',
      'lodash': '_',
      'sortablejs': 'Sortable'
    },
    plugins: [
      new CompressionPlugin({
        filename: '[path][base].gz',
        algorithm: 'gzip',
        test: new RegExp(`\\.(${productionGzipExtensions.join('|')})$`),
        minRatio: 0.8, // 压缩率小于1才会压缩
        threshold: 10240, // 对超过10k的数据压缩
        deleteOriginalAssets: false, // 是否删除未压缩的源文件，谨慎设置，如果希望提供非gzip的资源，可不设置或者设置为false（比如删除打包后的gz后还可以加载到原始资源文件）
      })
    ],
    // provide the app's title in webpack's name field, so that
    // it can be accessed in index.html to inject the correct title.
    name: name,
    resolve: {
      alias: {
        '@': resolve('src')
      }
    }
  },
  chainWebpack(config) {
    // it can improve the speed of the first screen, it is recommended to turn on preload
    // it can improve the speed of the first screen, it is recommended to turn on preload
    config.plugin('preload').tap(() => [
      {
        rel: 'preload',
        // to ignore runtime.js
        // https://github.com/vuejs/vue-cli/blob/dev/packages/@vue/cli-service/lib/config/app.js#L171
        fileBlacklist: [/\.map$/, /hot-update\.js$/, /runtime\..*\.js$/],
        include: 'initial'
      }
    ])

    // when there are many pages, it will cause too many meaningless requests
    config.plugins.delete('prefetch')

    // set svg-sprite-loader
    config.module
      .rule('svg')
      .exclude.add(resolve('src/icons'))
      .end()
    config.module
      .rule('icons')
      .test(/\.svg$/)
      .include.add(resolve('src/icons'))
      .end()
      .use('svg-sprite-loader')
      .loader('svg-sprite-loader')
      .options({
        symbolId: 'icon-[name]'
      })
      .end()

    config
      .when(process.env.NODE_ENV !== 'development',
        config => {
          config
            .plugin('ScriptExtHtmlWebpackPlugin')
            .after('html')
            .use('script-ext-html-webpack-plugin', [{
              // `runtime` must same as runtimeChunk name. default is `runtime`
              inline: /runtime\..*\.js$/
            }])
            .end()
          config
            .optimization.splitChunks({
            chunks: 'all',
            cacheGroups: {
              libs: {
                name: 'chunk-libs',
                test: /[\\/]node_modules[\\/]/,
                priority: 10,
                chunks: 'initial' // only package third parties that are initially dependent
              },
              elementUI: {
                name: 'chunk-elementUI', // split elementUI into a single package
                priority: 20, // the weight needs to be larger than libs and app or it will be packaged into libs or app
                test: /[\\/]node_modules[\\/]_?element-ui(.*)/ // in order to adapt to cnpm
              },
              commons: {
                name: 'chunk-commons',
                test: resolve('src/components'), // can customize your rules
                minChunks: 3, //  minimum common number
                priority: 5,
                reuseExistingChunk: true
              }
            }
          })
          // https:// webpack.js.org/configuration/optimization/#optimizationruntimechunk
          config.optimization.runtimeChunk('single')
        }
      )
  }
}
